Separating process



Oct. 6, 1925- R. ELLIS Filed March 9, 1925 lll/11111', T:

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Patented @et i925..

a srA'ras RIDSDAIE ELLIS, OIF OAK PARK, ILLINOIS.

SEPARATING PROCESS.

Application filed March 9, 1925. Serial No. 14,209.

T all 'whom it may concern:

Be it known that I, RIDSDALE ELLIS, a citizen of the United States, and a resident of Oak Park, in the county of Cook and 6 State of Illinois, have invented certain new and useful Improvements in Separating Processes, of which 'the following is a specification.

My invention relates to processes for conlo centrating ores and other materials by means of froth otation and the like.

This application is a continuation in part of my co-pending application Serial Number 345,137, filed December 15, 1919, which application was a renewal of application Serial Number 271,349, iled January 16, 1919.

The principal objects of my invention are in general to enhance the efficiency of such separating processes as hitherto carried out, more particularly bymeans of certain gases, and generally to improve the separation of comminuted materials by flotation.y

I have found that whereas in froth flotation emulsiiication and flotation are normally carried outin an atmosphere of ordinary air superior results are obtainable by the use of other gases more particularly oxygen. 1 5

I have further found that while an atmosphere of oxygen is useful in both emulsication and flotation the advantageous results obtained are nearly as great when oxygen is used in the emulsification treat- `ment only.

While the mixing of the ore with the modifying agent isthe primary purpose of the emulsiication treatment such treatment also involves aeration of the ore pulp, aeration also takes place to a more limited extent 1n the tube mill or other grinding apparatus which may be employed.

The precise cause of the beneficial effects produced by the use of oxygen in place of air and of air in place of nitrogen are uncertain. It is believed,l however, that one of the factors involved is the contact and other electrical effects occurring at the gaswater,`-gasparticle and other interfaces.

Suitable electrical conditions favor the adhesion and it has been found that chemical action either complete or incipient greatly increases the electrification of gases. rIhus a gas bubble generated chemically in water is much more highly charged than one introdit duced bodily from the surrounding atmosphere.

Now of the constituents of air only one is chemically active, viz oxygen, and I have found that this constituent is the active one in flotation, the extraction of a zinc ore, for example, being much higher in an atmosphere of oxygen than in one of air.

Further I have found that in certain cases of ozonizing the air in which the ore pulp is agitated aids the extraction, especiall when the quantity of frothing agent is small Substantially pure oxygen is, however, ordinarily superior to ozonized air which necessarily contains allof the nitrogen contained in the original air.

Il have also found that the advantageous results obtainable by the use of oxygen in place of air are much more marked in the case of a relatively diflicultly floatable ma- 75 terial, like zinc sulphide, than in the case of relativelyT easily floatable material, like copper sulphide.

In practice carried out by me on a zinclead ore assaying about 18% of zinc I have found that by mechanically agitating the ore pulp in an atmosphere of oxygen instead of air the percentage of zinc remaining in the tails was reduced about 50% when both emulsication and aeration take place in oxygen and about 35% when only emulsication is carried out in an atmosphere of oxygen.

It will be understood that in addition to oxygen any suitable reagents may be employed, such as copper sulphate and sulphuric acid in the casev of zinc ores.

Further, a soluble frothing agent may be employed in place of the oil either wholly or in part. Similarly a frothing agent in vapor form may be used in place of or in addition to the liquid oil as soluble frothing agent. l

The various forms of apparatus commonly employed for carrying out the sepa- 10o ration of metalliferous matter by flotatlon are so well known to those skilled in the art that the diagrammatical sectional illustration in the drawings of a flotation machine' of the mechanical agitation type will 105 suflice.

The apparatus comprises an emulsifier cell 1, a frothing cell 2 and a separating chamber or spitzkasten 3. In the emulsiier cell 1, an agitator 4.- is provided, mounted at the tie end of a shaft 5, rotated'by means of a shaft- 6, connected thereto by means of bevel gears l 7 and 8. The ore pulp is fed into the emulsifier through the pipe 9. Oil is-fed into the b emulsifier through the pipe 10. As a result of the agitation in the emulsifier the inetallil'- erous particles in the ore pulp become coated With the oil and then the ore pulp passes through the passage 11 into the frothing cell 2. In the latter is arranged an agitator 12 mounted on a shaft 13 driven from the shaft 6 by means of bevel gears 14 and 15.

The lower part of the cell 2 is connected with the spitzkasten by an aperture 16 15 through which passes the ore pulp after being aerated inthe cell 2. In the spitzkasten the gangue sinks-to the bottom While the metalli-ferons matter adhering to bubbles of gas are rafted to the surface of the pulp to form a layer of froth 17'on the surface of the Water. The froth flows over a lip 18 into the launder 19 from which the concentrates including any froth Which has not been broken down in the launder maybe Withdrawn through pipe 20.'

The tails, consisting of silica, silicates, etc., sink to the bottom ofthe spitzkasten 3 and collect in the hopper-shaped part 21 from which they may be sent by pipe 22 either to the tailing pond or else to a second chamberl for further treatment.

In order that the ore may be mixed With the modifying or frothing agent in an atmosphere of oxygen ora gaseous mixture containing a higher percentage of oxygen than air the upper vpart of the emulsifer 1, is enclosed by a cover 23. A gas inlet pipe 24 and outlet pipe 25 are provided so that oxygen may be admitted and exhausted after it has become diluted with nitrogen orv other gases `released from 'solution in the water of the ore pulp.

Preferably the upper part of the frothing cell 2, is similarly enclosed at 26 andoxygen supplied thereto by means of a pipe 27. The

oxygen from the frothing cell may conveniently be discharged into the inlet pipe 24 of the emulsier. This counter current arrangement is preferred as the greatest contamination of oxygen by nitrogen from the water in the ore pulp Will be in the emul- .sifien While I have illustrated and described my invention in connection with the mechanical agitation froth process it may also be used by dissolving it in the Water'and then liberating it by the action of heat or pressure re- ".5 duction, by chemical reaction, by the decomposition of such substances as hydrogen peroxide or by electrolysis or similar means.

Further, While ordinarily oxygen used in connection with a mechanical agitation froth apparatus is generated outside of the pulp it is not essential to do so and the necessary supply of oxygen may be formed in the pulp by electrolysis or' other means.

l am aware thatnuinerous details of the lpulp with a modifying agent, aerating the pulp to form a froth and separating the froth from the remainder by flotation, and which furtherincludes the use of an externally prepared gas containing more than 25% free oxygen by .volume for aiding in the formation of the froth.

2. The process of concentrating ores by flotation which includes fmixing the ore pulp With a modifyingagent, aerating the pulp at substantially atmospheric pressure to form a froth andseparating the froth from the remainder by flotation, and which further includes subjecting the ore pulp to a gas containing more than 25% free oxygen by volume during lsaid mixing step.

3. The process of concentrating ores by flotation which includes mixing the pulp with a modifying agent to coat the mineral particles, aerating the pulp aty substantially atmospheric pressure to form a froth and separating4 the froth from the remainder by flotation, and which further includes the use of a gas containing more, than 25% y free of the particles.

, oxygen by volume for aiding in the coating 4. The process of concentrating ores which includes aerating the pul with an externally prepared gas containing more than 25% free oxygen by volume to form a froth, and separating the mineral carried by the froth from the remainder of the ore.

5. The process of concentrating ores Which includes producing bubbles of gas in the ore pulp to form a froth, substantially all of which bubbles contain over'40% free oxygen by volume, and separating the mineral carried by the froth from the remainder of the ore. v

6. The process of concentrating ores by flotation which includes mixing the ore pulp with a modifying agent, aerating the ulp to form a froth and separating the roth from the remainder by flotation, and which further 4includes the use of a gas containing more than 40% free oxygen by volume for aiding in the formation of the froth.

7. The process of concentrating ores by cludes the use of a gas containing more than Ll0% free oxygen by volume for aiding lin the coating of the particles.

S. The process of concentrating ores which includes mixing the ore pulp With a modifying agent, aerating the pulp with an eX- ternally prepared gas having a substan- `tially greater direct oxidizing power than atmospheric air to form a froth, and separating the mineral carried by the froth from the remainder of the ore.

9. The process of concentrating ores which includes mixing the ore pulp with a modifying agent to coat the metalliferous'particles,`aerating the ore pulp at substantially atmospheric pressure to form a froth and separating the froth from the remainder by flotation and which further includes the use of a gas having asubstantially greater oxidizing power than atmospheric air to aid in the coating of the particles.

10. The process of concentrating ores by flotation Which includes mixing the ore pulp with a modifying agent, aerating the pulp to form a froth and separating the froth from the remainder by fiotation, and which further includes the use of substantially pure oxygen for aiding in the formation of a froth.

RIDSDALE ELLIS. 

